Welding Facts for Kids

Gas metal arc welding

Welding is a cool way to join pieces of metal together. It works by heating the metal until it melts and then sticks. Think of it like using super-strong glue, but with heat! There are many types of welding. Some use electricity to create a very hot spark, called an electric arc. Others use a flame or even just strong force.

It's super important to be safe when welding. The bright light from arc welding can hurt your eyes, so welders always wear a special helmet or goggles. Also, hot sparks can fly, so welders cover all their skin to avoid getting burned, kind of like a bad sunburn.

Arc Welding Basics
- Electrodes in Arc Welding
- Protecting the Weld
  - Using Flux for Protection
  - Using Shielding Gas for Protection
Other Ways to Weld
Energy for Welding
- Power for Arc Welding
- Energy for Other Welding Types
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Arc Welding Basics

Arc welding is a common way to join metals using a powerful electric arc. This arc is like a super-hot spark that melts the metal pieces.

There are a few main types of arc welding:

Shielded metal arc welding (SMAW): People often call this "stick welding."
Gas metal arc welding (GMAW): This is also known as MIG welding.
Gas tungsten arc welding (GTAW): You might hear this called TIG welding.

In arc welding, the electric arc forms between the metal you're joining and a special metal rod or wire called an electrode. This arc gets so hot it melts the metal.

Electrodes in Arc Welding

The electrode is a key part of arc welding. It's usually made of the same kind of metal you're welding.

In "stick" (SMAW) and MIG (GMAW) welding, the electrode melts and becomes part of the weld. It's like adding extra metal to fill the gap.
Stick welding uses a rod covered in a special material called "flux."
MIG welding uses a thin wire that comes off a spool, like a giant roll of string. A small motor in the welding machine feeds this wire continuously.

TIG welding (GTAW) is different. Its electrode is made of Tungsten, which doesn't melt. Instead, a separate filler rod is used to add metal to the weld if needed.

Most welding uses extra metal, called "filler metal," to make the weld strong. Sometimes, though, welds are made without any filler metal. This is called autogenous welding.

Protecting the Weld

When metal gets super hot during welding, it needs protection. Things like dirt, rust, or even air can cause problems. To keep the weld strong and clean, welders use two main methods: flux or shielding gas.

Using Flux for Protection

Flux is a special material that can be a solid, liquid, or paste. When it melts during welding, it creates a small cloud of gas around the hot metal. This gas keeps normal air away, especially oxygen, which can weaken the weld.

Melted flux also helps clean the metal. After the weld cools, the flux turns into a hard layer called "slag." This slag needs to be removed from the weld. Stick welding often uses flux, especially for welding steel.

Using Shielding Gas for Protection

Shielding gas is another way to protect the weld. It creates a pocket of gas around the hot metal, keeping air out. Unlike flux, shielding gas doesn't clean the metal. This means the metal must be very clean before you start welding.

Common shielding gases include argon, helium, or a mix of argon and carbon dioxide. Sometimes, other gases like nitrogen or a little bit of oxygen are added. MIG welding often uses shielding gas. It's great for factory work.

Welding with flux is often better for outdoor jobs, especially if it's windy. The liquid flux helps protect the weld even if the wind blows. Shielding gas can blow away in the wind, making it harder to weld outdoors.

Other Ways to Weld

Not all welding uses an electric arc. Some methods use a flame, electricity without an arc, or even just physical force.

Gas Welding

One common type of welding without an arc is gas welding. It uses a flammable gas, usually acetylene, mixed with oxygen. This mix burns at the end of a torch, creating a very hot flame that melts the metal. When the edges of two metal pieces melt, they join together.

Resistance Welding

Another type that uses electricity but no arc is resistance welding. Imagine pinching two thin pieces of metal together. Then, electricity is sent through them. This makes the metal get super hot and melt right where it's pinched. This is often called "spot welding" because it joins the metal at one small spot.

Forge Welding

Forge welding is one of the oldest ways to weld. Blacksmiths used it long ago! They would heat two pieces of metal until they were almost melting. Then, they would hammer them together until they became one solid piece.

Modern Welding Methods

Some newer welding methods are very advanced and often expensive. They might use powerful electron beams, lasers, or even ultrasonic sound waves to join metals. These are usually used for very specific jobs.

Energy for Welding

Every type of welding needs energy. Most often, this energy is heat, but sometimes it's mechanical force.

Power for Arc Welding

Arc welding uses a lot of electricity. Some welders use alternating current (AC), like the power in your house. Others use direct current (DC), like the power from a battery. Welding machines are special power supplies that take electricity from a power plant and make it safe and usable for welding. They control the voltage and current.

Some welding machines don't plug into a wall. They have an engine that runs a generator to make their own electricity. These engines might run on gasoline, diesel fuel, or propane.

Energy for Other Welding Types

Gas welding (OFW) uses a flame from burning fuel gas and oxygen. Acetylene is the most common fuel gas because it burns hotter than any other gas. Other gases like propane or natural gas can also be used.

Some welding methods don't melt the metal at all. Forge welding is one example. Another cool one is friction stir welding. This method uses a powerful motor and a special spinning tool to mix the metals together at their edges. It takes a lot of force because metals are solid! The energy for this comes from the spinning tool's mechanical movement.